FIG. 1 shows a structure of System Architecture Evolution (SAE). User Equipment (UE) 101 is a terminal device used for receiving data. Evolved Universal Terrestrial Radio Access Network (E-UTRAN) 102 is a radio access network including eNodeB (eNB) which provides a radio network interface for the UE. Mobility Management Entity (MME) 103 is responsible for managing mobile context, session context and security information of the UE. Serving Gateway (SGW) 104 mainly provides user plane functions. MME 103 and SGW 104 may be located in the same physical entity. Packet data Gateway (PGW) 105 is responsible for functions such as charging and legal listening. PGW 105 may be located in the same physical entity with SGW 104. Policy and Charging Rule Function (PCRF) 106 provides Quality of Service (QoS) policies and charging rules. Serving GPRS Support Node (SGSN) 108 is a network node device providing routes for data transmissions in Universal Mobile Telecommunications System (UMTS). Home Subscriber Server (HSS) 109 is a home subscriber subsystem of the UE and is responsible for saving user information such as current position of the UE, address of the serving node, user security information and packet data context of the UE.
With the increasing of the service data rate of the UE, supporting of Selected IP Traffic Offload (SIPTO) and Local IP Access (LIPA) capabilities is proposed in 3GPP. In the SIPTO, when the UE access the Internet or other external networks via a Home Evolved NodeB (HeNB), a Home NodeB (HNB) or an eNodeB/NodeB, the network may select or re-select a user plane node which is closer to the radio access network. When the UE access a home network or an enterprise network via the HeNB or the HNB, a user plane node closer to the HNB or a user plane node in the HeNB/HNB access network may be selected or re-selected for the UE during the LIPA. The user plane node may be a core network device or a gateway. For the SAE system, the user plane node may be the SGW or PGW or LGW. For the UMTS system, the user plane node may be the SGSN or GGSN.
At present, there are two kinds of service scenarios in the standards, one is LIPA service supporting local network, and the other is SIPTO service supporting local network. For the two kinds of services, the same network architecture or different network architectures may be used. Differences between the two kinds of services include the following.
The LIPA service supporting local network only allows a Closed Subscriber Group (CSG) member to activate the LIPA service. When the user moves within the local network, service continuity of the user is maintained. When the user moves out of the local network, the LIPA service is broken.
The SIPTO service supporting local network allows both the CSG member and a non-CSG member (e.g., a user accesses via hybrid HeNB) to activate the SIPTO service. When the user moves within the local network, service continuity of the UE is maintained. When the user moves out of the local network, a service type that the user requested and an operator's policy are utilized to determine whether the service should be broken. For example, if an identifier corresponding to an APN of the current service indicates that the service is supported only by the local network, the service will be broken and not re-established when the user moves out of the local network. if the identifier corresponding to the APN of the current service indicates that the SIPTO service may be activated under a base station outside or inside the local network and if the operator's policy is keeping the continuity of the service after the UE moves out of the local network supporting the SIPTO service, the continuity of the current service of the UE is maintained after the UE moves out of the local network, and the network may re-activate the SIPTO service for the UE later and re-select a new user plane node device for the UE.